Agitator for centrifugal spreaders



March 11, 1969 H. DREYER AGITATOR FOR CENTRIFUGAL SPREADERS Filed July 28. 1965 nvvavro/z HE/NZ DREYER m Emmy a 6M ATTORNEYS United States Patent 0.

9 Claims ABSTRACT OF THE DISCLOSURE The specification discloses a novel agitator which is particularly useful in the dislodgement of particulate material and, especially, fertilizer material. The agitator described herein is unique specifically in that it comprises a drive shaft operatively associated with a drive means on one end thereof and operatively associated with an agitator shaft at the other end thereof. The agitator shaft is aligned, at least partially, nonaxially with the drive shaft. The agitator shaft further has agitator elements extending radially therefrom at some angle to the agitator shaft axes and may have a bearing means disposed intermediate the end thereof connected with the drive shaft and the end thereof remote from the drive shaft. Preferably, the bearing means is located intermediate the ends of the agitator shaft. Further preferably, the agitator shaft is composed of a multiplicity of generally parallel, nonaligned, operatively associated sections which are adapted to revolve around the general center line of the agitator.

The invention relates to an agitator for centrifugal spreaders.

More particularly, the invention relates to such spread-r ers for spreading mineral fertilizers, and which contain an agitator shaft positively connected to a drive shaft, and possessing at least one agitator element which, when said drive shaft rotates, carries out a reciprocating and/or circular movement directed mainly perpendicularly to the central axis of said agitator. It is an aim of the invention to solve the problems of obtaining a continuous and trouble-free flow, even of moist and caked types of fertilizer, towards the outlet passages of the storage container of the machine, at the same time avoiding any damage to the agitator or the container walls, however full the storage container may be.

A known agitator of this type of construction is already disclosed in British Patent No. 683,299. This agitator consists of an. agitator shaft rigidly connected to the drive shaft, the upper bent end of said agitator shaft being parallel with the upwardly extended center line of the drive shaft, so that when said drive shaft rotates, said agitator circles around said center line. Rotatably mounted on said upper end of the agitator shaft is a bush, to which are attached four agitator rods which first extend radially and horizontally outwards and then bend upwardly almost parallel with the wall of the container. During operation, these agitator rods move or circle with the bearing bush in a horizontal plane.

The disadvantage of this agitator is that the distance between the attachment location of the agitator shaft to the drive shaft and the upper agitator-rod ends is so great that the agitator shaft and the agitator rods twist or bend as a result of the forces arising during operation. If this twist is elastic, either the agitator effect is reduced to an ineffective minimum or an up and down tamping movement of the horizontal agitator-rod parts occurs, and this results in a compacting rather than a loosening of the fertilizer with which it comes into contact. Compacting occurs to a still greater degree in the case of permanent deformation, especially of the agitator shaft. This may be attributed to the fact that in the case of a 3,432,150 Patented Mar. 11, 1969 permanent outward twist in the agitator shaft, the circling movement of the agitator rods isgreater in diameter than when the agitator shaft is not twisted. In addition to this, the bent upper portion of the agitator shaft now 7 assumes an inclined position in relation to the upwardly extended center line of the drive shaft. The result of this is that in addition to the bent portion of the agitator shaft, both the outwardly and the upwardly directed agitator-rod parts each move on the peripheral surface of an imaginary conical body, and are pressed into the fertilizer at their greatest cross-section, as a result of which the already-mentioned disadvantageous compactmg, instead of loosening, action occurs. The same disadvantageous result is obtained when the permanent twist of the agitator shaft is inward, so that approximately the center point of the bush lies upon the upwardly extended center line of the drive shaft, and the upper bent end of said agitator shaft assumes :an inclined position in relation to the center line of said drive shaft. The difference is merely that in the latter case the tapering portion of each conical movement body for the upright agitator rods no longer points downwards but upwards. There is also the danger that, as a result of this permanent twist and the more violent movement of the agitator parts associated therewith, the forces acting upon the agitator may become so great that the agitator rods come into contact with the container wall and either become bent themselves or damage the container wall. The fact that as a result of the arrangement and configuration of the agitator rods, there arises the additional disadvantage that the central area of the storage container is not acted upon, so that clumps of fertilizer can arise in this area which must lead to interruptions in the flow of fertilizer, will not be taken into account in this review.

Another known agitator contains an agitator shaft in the form of a crankshaft on which one or more agitator elements are rotatably mounted, and which is articulately attached by its lower end to the drive shaft. In most cases the resulting agitation is adequate and the power requirements relatively small. There is, however, the disadvantage that as the storage container empties, the agitator strikes against the container wall; since the agitator ele ments execute movements perpendicular to the center line of the agitator, these strikes are relatively heavy. In time the hopper wall becomes damaged and, at the same time, deformation of the agitator occurs. There is also the disadvantage that the strikes produce a sharp knocking sound.

The present invention eliminates these disadvantages in that the agitatorshaft is attached not only to the drive shaft but also to another location on the machine. According to the invention, there is provided an agitator for a centrifugal spreader fitted with a container, comprising an agitator shaft mounted for rotation. within the container, at least one agitator element mounted on the said shaft, the latter being connected at one end to a drive shaft and being further supported by at least one bearing longitudinally spaced from the said end and so shaped that when the drive shaft is rotated the agitator element executes a reciprocating and/or circular movement mainly perpendicular to an axis passing through the said bearing and the said end of the agitator shaft.

The hearing may be attached in the lower area of the container, or still better, farther up the storage container on the container wall, or it may even be connected to parts of the machine frame.

These steps provide the following advantages:

The lateral forces arising during operation are absorbed by the additional bearing, thus ensuring that the movement of the agitator elements is perpendicular to the center line of the agitator, as desired, and that no larger bending moments can act upon the agitator shaft. Furthermore, it is impossible for the agitator to come into contact with the container wall, even if the agitator-shaft bearings are somewhat worn, or when sudden strong lateral forces arise as a result of obstacles in the fertilizer. The possibility is also provided of shaping the agitator elements in such a manner that they may be carried from their bearing location up to close against the container wall, thus ensuring a particularly advantageous and thorough turning over of the fertilizer in the storage container over the whole range of the agitator, as well as adequate removal from the container wall any possible adhering fertilizer residues.

In further pursuit of the concept of the invention it is proposed that the agitator shaft be connected to the drive shaft in known fashion per se by means of a universal joint or flexible coupling, and that the additional bearing may be arranged detachably and adjustably. In a storage container, the cross-section of which is made asymmetrical for specific reasons, this arrangement makes possible adequate stirring of all of the spreading material in the storage container, and to subject to special agitation any locations in which the fertilizer settles easily. It is also possible to withdraw the agitator to simplify the cleaning of the storage container.

The invention also foresees that the attachment of the additional bearing will be above at least one agitator element and will be connected to the container walls. This step results in particularly stable retention of the agitator.

The invention is illustrated by way of example in the attached drawings, wherein:

FIGURE 1 shows, in cross-section, a centrifugal spreader equipped with an agitator, and

FIGURE 2 shows in section the adjustable arrangement of the additional bearing, to a different scale.

The centrifugal spreader includes a storage container 12 which tapers towards the bottom end and is adapted to receive mineral fertilizer. Mounted for rotation within the container is an agitator shaft 1 equipped with four parts 2, 3, 4 and 5 bent in relation to each other and agitator elements 6, 7 and 8 rotatably mounted on bent parts 2, 3 and 5. Elements 6 are in the form of straight rods and elements 7 are in the form of bent rods. The lower end of agitator shaft 1 is connected to drive shaft 10 by means of universal joint 9. Beneath floor plate 11 of storage container 12 is a slinger disc 13 attached to said drive shaft 10. Bent part 4 is for the rotatable arrangement of agitator shaft 1 in bearing 14, said bearing being detachably mounted, with the aid of bolts 15 to curved rail 16 leading from the steeper container wall 17 to the fiat container wall 18. In order to make this arrangement of bearing 14 adjustable, several holes 19 are made in rail 16.

During operation, i.e., when drive shaft 10 is rotating, agitator elements 6, 7 and 8 execute circling and/or reciprocating movement perpendicular to agitator center line or axis 20 as a result of being rotatably mounted on agitator shaft 1, and therefore penetrate into the fertilizer in storage container 12 with their smallest crosssection. This ensures an undisturbed flow of fertilizer towards outlet 21, and there can be no compacting of fertilizer, or damage to agitator elements 6, 7 and 8, or to the contaner wall 17 and 18 as a result of striking.

What is claimed is:

1. An agitator for a centrifugal spreader disposed within a container, comprising a drive means operatively associated with a drive shaft, wherein said agitator shaft consists of a multiplicity of sections, at least one of which sections is disposed in spaced relationship with the general centerline of said agitator shaft and operatively associated with other sections of said shaft, wherein said spaced agitator shaft section has at least one agitator element projecting generally radially therefrom, and wherein said agitator shaft is supported by a bearing at a point intermediate its ends, which point is substantially coincident with the general center line of said agitator shaft.

2. An agitator according to claim 1 wherein the said agitator shaft is connected to the said drive shaft by a universal joint so as to permit the said bearing to be offset from the axis of the drive shaft.

3. An agitator for a centrifugal spreader as claimed in claim 2, comprising an agitator shaft mounted for rotation within the container, at least one agitator element mounted on the said shaft, the latter being connected a one end to a drive shaft and being further supported by at least one bearing longitudinally spaced from the said end, which bearing is adjustable in position obliquely with respect to the longitudinal direction, which agitator element is so shaped that when the drive shaft is rotated said agitator element executes a reciprocating and/ or circular movement substantially perpendicular to an axis passing through the said bearing and the said end of the agitator shaft.

4. An agitator according to claim 3 wherein there are a multiplicity of agitator elements in the form of rods.

5. An agitator for a centrifugal spreader as claimed in claim 4, wherein at least some of said agitator elements are rotatably mounted on a throw portion of said shaft, which shaft is connected at one end to a drive shaft and is further supported by at least one bearing mounted upon and within said container, which bearing is longitudinally spaced from the said end, said throw being so shaped that when the drive shaft is rotated, the agitator element executes a reciprocating and/or circular movement mainly perpendicular to an axis passing through the said bearing and the said end of the agitator shaft.

6. An agitator as claimed in claim 1 which is adapted for spreading mineral fertilizer, and wherein said container is tapered toward the end thereof proximate said drive shaft.

7. An agitator as claimed in claim 1 wherein said agitator shaft has sections containing agitator elements disposed on both sides of said bearing.

8. An agitator as claimed in claim 1 having a multiplicity of sections generally parallel to and spaced from said agitator center line.

9. An agitator as claimed in claim 8 having agitator elements disposed substantially radially from each of said agitator shaft sections.

References Cited UNITED STATES PATENTS ROBERT W. JENKINS, Primary Examiner. 

